http://www.ebay.com/itm/New-AC-100-240V-Digital-Twin-Timer-4-Digitals-Tact-Switch-OMRON-Relay-Output-/160690244285?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%26itu%3DUA%26otn%3D5%26pmod%3D150678387096%26ps%3D63%26clkid%3D4548878490510667888
Looks like this would be a good timer for an aero unit, as long as the "cycle" mode operates as expected (on for xx seconds, off for xx seconds, repeat). In addition, you'll need to know at least a little bit about electricity/electronics, relays, and GFI circuits to wire this up to your pumps without lighting yourself up.